LIPIDS OF FISH PARASITES AND THEIR HOSTS - FATTY-ACIDS OF PHOSPHOLIPIDS OF PARATENUISENTIS-AMBIGUUS AND ITS HOST EEL (ANGUILLA-ANGUILLA)

The fatty acid composition of various phospholipid classes, e.g. phosp hatidylcholines, phosphatidylethanolamines, phosphatidylserines and sp hingomyelins, of the fish endoparasite Paratenuiseratis ambiguus and o f intestinal tissue of its best, eel (Anguilla anguilla), were investi gated. Phospholipids from parasite and infected host intestine show co nsiderable differences in the fatty acid compositions. High proportion s of saturated long-chain and very long-chain acyl moieties were found in phosphatidylcholines, ethanolamines and serines of the parasite. M embrane phospholipids of P. ambiguus contain remarkably high proportio ns of polyunsaturated acyl moieties, in particular eicosapentaenoyl mo ieties (20:5 n-3), which undoubtedly originate from aquatic feed or ho st intestine. It is suggested that the parasite's membranes are stabil ized by incorporation of high proportions of saturated long-chain and very long-chain fatty acids to counterbalance tbe destabilizing effect s of the polyunsaturated fatty acids.